CLDN18 and cholangiocarcinoma: However, the Kaplan–Meier curve revealed no difference in OS between CCA patients with presence [47.74 months, 95% confidence interval (CI) = 24.46–71.03 months] or absence (43.85 months, 95% CI = 33.24–54.46 months) of moderate‐to‐strong membranous CLDN18 expression (P = 0.713; Supporting information, Figure S3).